Molecular contamination is a fundamental issue in semiconductor manufacturing, specifically, in tools that include vacuum chambers, such as scanning electron microscopes. Organic molecules may originate from organics component inside the vacuum chamber, as well as from wafers that were previously inserted into the vacuum chamber. These organic molecules are absorbed on the surface of the inspected wafer, to form islands that cover fractions of the surface. These island may result in wafer malfunctions. The cleanliness level varies with time due to maintenance activities and the outgassing level of the inspected wafers.
There is a growing need to provide a device and method for monitoring the cleanliness of vacuum chambers.